“We believe that the Canadian banking sector is encountering incremental pressure from headwinds facing the Canadian economy, which is heightening economic risk in the banking system,” S&P said in announcing the downgrades.

It added that it expects intensifying competition for loans and deposits “will lead to pressure on profitability growth, especially in banks’ retail businesses.”

The firm lowered its ratings by one notch on Scotiabank (TSX:BNS) to A-plus. National Bank of Canada (TSX:NA), Laurentian Bank of Canada (TSX:LB), Central 1 Credit Union , Caisse centrale Desjardins and Home Capital Group (TSX:HCG) were also lowered one notch.

S&P also affirmed its credit ratings on the Royal Bank (TSX:RY) and TD Bank (TSX:TD) and raised its outlook to stable from negative. The agency currently rates both banks at double-A-minus.

A downgrade by a credit rating agency usually means investors will demand a higher interest rate when a company goes to raise cash by issuing bonds or other debt.

Moody’s had already cut Royal Bank’s long-term deposit rating to Aa3 from Aa1 in June as part of a move to cut the credit ratings of 15 of the world’s largest banks, including Bank of America, JPMorgan Chase, Citigroup and Goldman Sachs.

At the time, the agency noted that RBC had stronger buffers than many of its global peers in the form of earnings from other, generally more stable businesses.